The art of generating light from chemical energy has been practiced for many years. Chemiluminescent light of appreciable yields (e.g., that which one could read a newspaper by) has only been in practice, however, since the early 1970's.
U.S. Pat. No. 3,749,679 (Ruhut), U.S. Pat. No. 4,751,616 (Smithey), U.S. Pat. No. 3,888,786 (Maulding), and U.S. Pat. No. 3,816,326 (Bollyky), are fairly descriptive of such chemiluminescent systems. Additionally, it was about that time that commercial fisherman learned that this new generation of chemiluminescent lures were useful in attracting swordfish and tuna (as well as other species).
For catching swordfish and tuna, a "longline" vessel is generally used. A typical longline vessel will employ the use of one or more main line spools capable of holding thirty to sixty miles of 700-1200 pounds tensile strength nylon monofilament line. This mainline is supported through a series of buoys evenly placed throughout its length, and is usually dispensed in its entirety with 300 to 900 separate leader lines evenly dispersed (usually called a "set"). The length of these leader lines determines the depth of fishing. At the end of each leader line is a hook with, typically, a one pound squid attached as bait. The chemiluminescent lure is usually attached from one to ten feet from the bait. The purpose of this lure is to attract swordfish and tuna (tuna species generally being BIGEYE, YELLOWFIN, and BLUEFIN) to the bait from a range that exceeds their sense of smell. Curiosity about the light source generally attracts the fish to within the "smell" range of the squid, thus causing the fish to take the bait and be caught.
This entire process of placement and retrieval is repeated every twenty-four hours for the entire trip length (usually 7 to 28 days). Since the nature of chemiluminescence is that the average "glow" life is between about 12 to 18 hours, the spent lures must obviously be removed every set and discarded in favor of new ones.
This obviously demonstrates the relatively high cost in tackle for the operation, thereby making great the need for maximizing the catch ratio for each lightstick lure utilized. Another problem is that certain colors of chemiluminescent lures may not always work well under various defined conditions. Conditions such as water clarity, depth, time of day or night, and water temperature can all have an effect on the fishermen's yield using any particular color of lightstick.
Theory in practice has proven that the targeted species of fish attracted by chemiluminescence interpret and respond to various wavelengths of light differently. For example, in 68.degree. F. murky water at 50 fathoms, night fishing, a blue chemiluminescent lure might attract swordfish, whereas under the same conditions a tuna might not respond to the color displayed. Likewise, under a different set of conditions, a tuna might be attracted to a green chemiluminescent lure, while a swordfish would not.
Attempts have been previously made by fishermen to increase their catch by attachment of two separate and different colored lures. This method was generally deemed inefficient and impractical due to the radical increase in cost of doubling their gear, and likewise doubling the required labor and time to attach two separate lures onto each single leader line.
Since the chemiluminescent lure is generally attached to the leaders by mean of a rubberband, the attached lure usually hangs in whichever direction gravity and/or water current dictates.
When two lures, each of a different color for example, are attached to the leader, they are susceptible to the same currents and water movements, often forcing them to hang in an aligned or side by side manner. As used herein, the term "aligned" is used to connote the condition where two or more color tubes are closely adjacent one another and at least partially overlapping, parallel, or superposed on one another such that radiation energy from one color tube is at least partially blocked by the other tube. This aligned configuration causes the effective appearance of only one color of light being emitted (or at least drastically reduced effectiveness of at least one of the colors), especially when diffused by water. In any event, the effectiveness of the colors, and of the luminescent lure overall, is significantly reduced or negated when the color tubes are aligned.
The term "chemiluminescent" as used herein, means a substance (usually a mixture of light affecting material) which emits light by chemical reaction.
The term "light" as used herein, is defined as electro-magnetic radiation at wavelengths falling in the visible spectrum, such as between about 350 and 800 millimicrons.
The term "two component chemiluminescent system" as used herein, means generally a clear flexible tube containing one component, with a frangible ampule housed inside the tube and containing a second component that, when said frangible tube is fractured, mixes with the first component producing light. An aromatic ester of oxalic acid in a suitable solvent (the "oxalate component"), usually preferably comprises the first component of a two component chemiluminescent system. A solution of a hydrogen peroxide compound, a hydroperoxide compound, or a peroxide compound in a suitable solvent (the "peroxide component"), usually preferably comprises the second component of a two component chemiluminescent system.
The terms "frozen" or "low-temperature storage" luminescent color tubes will be used herein to connote a premixing of chemiluminescent components, filling tubing with the components, and immediately cooling and maintaining the tube at very low temperatures by the means of dry ice, low temp freezers, or the like, to inhibit the chemical reaction until the tube (lure) is used.
Generally, light activation in the above-noted types of devices is of two basic types. In one type, a frangible glass ampule contains one component of the chemiluminescent system, with the remaining or second component of the chemiluminescent system being contained within the hollow interior of the color tube. When the ampule is broken, as by bending the tube the chemiluminescent materials mix together producing visible light as described above. The second approach, mentioned above, requires premixing the chemiluminescent materials, then maintaining the tubular packaging at a very low temperature by means of dry ice or the like to inhibit the chemical reaction until the display is used. Typical examples of these types of containers are described in U.S. Pat. Nos. 4,508,642 and 4,061,910.